Control for electric circuits



July 16, 1929. G. MUFFLY 1,721,163

CONTROL FOR' ELECTRIC CIRCUITS Filed Nov. 5, 1926 grvverntod Gnozwaq Patented July 1e, 1929.

UNITED STATES GLENN MUFFLY, OF DETROIT, MICHIGAN.

CONTROL FQR ELECTRIC CIRG' ITS.

Application led November It is the primar object of my invention to provide a contro for electric circuits, and particularly one adapted for use in electric refrigeration system, for controlling the oper- 5 ation of the electric motor and compressor in accordance with the temperatures obtainingin the refrigerator'box. In accomplishing this, I provide a sylphon mounted outside the refrigerator box and connected by a tube with the interior of the box, said tube containing a gas adapted to expand andcontract the sylphon-in accordance with temperature variations. I connect a mercury tube or other suitable circuit making and breaking devices with the sylphon in such a manner that the tube and the sylphon will be tilted by expansion or contraction so as to make or break the electric circuit.y

With the above and other objects in view,

my invention consists in the arrangement, combination and construction of the various parts of my improved device, as described 1n the specification, claimed in my claims and shown in the accompanying drawing, 1n

which:

The single figure is a central sectional view showing diagrammatically a refrigerator box with my improved device applied thereto.

I have shown a refrigerator box or cabinet having a conventional food compartment 6 and freezing compartment 7. In the freezing compartment 7 I have conventionally shown a freezenor brine tank 8 into which a tube 9having an enlarged end 10 is extended. The bottom of the end 10 is sealed and a supply of liquid which will gasify in thelpresence of certain temperatures is contained therein, as shown at 11.

Mounted on the topof the box 5 by means of screws 12 is a plate 13 having struck-up portions 14 and 15 from which screw-threaded standards 16 and 17 extend. Mounted on another struck-up portion 18 of the plate 13 is a conventional sylphon bellows 5() having a top closure 19 and a single opening which communicates with the tube 9 as at 20. The sylphon is provided with a central depression 21 in which the depression 224 of a plate 23 seats. The plate 23 is provided with a struckup portion 24 which is apertured to receive the standard 17. A nut 25 is screwed on the standard 17 against the top of the struckup portion 24 so as to anchor the same in' any desired position. The opposite end of the plate 23 is provided with an apertured depression 26 through which the standard 16 s, 192e. serial No. 146,375.

extends. Positioned around the standard 16 above the plate 23 and seating in the depression 261s a coil spring 27. A flanged washer y28v is provided on the` top of the-.spring 27 and a nut 29 is threaded on the standard 16 so as to adjustably hold'the spring 27 under compression and thereby exert an adjustable and yieldable pressure upon the plate23.

Positioned above the plate 23 and secured thereto by means of a strap 30 and screw 31 is a conventional mercury tube 51 adapted to contain a drop of mercury, and having electric leads 32-and`33 extending therefrom. A hood 34 is provided over the operating parts ofthe control, being suitably apertured as at 35 and 36 so that the standards 17 and 16 may extend therethrough and bearing at its bottom against the plate 13. Nuts 37 .and l38 are provided on the standards 17 and 16, respectively, above the top of the hood so as to removably secure the hood in place.

In the practical operation of my improved device, when the temperature in the freezing chamber 7 or freezer 8 is above a predeter- 30 mined level, the liquid contained in the tube 9 w1ll gasify and expand into 'the sylphon 5() thereby causing the sylphon to expand and raise the plate 23 against the pressure of the spring 27 until the mercury tube 51 is tilted to bring the mercurv drop therein to the end of the tube' where the electric terminals are positioned (as viewed in the drawing, the left hand end of the tube would be raised to bring the drop of mercury to the right'hand 90 end thereof). Whenthe* operation of the refrigerating appartus has continued to the point where the temperature .in the freezer 8 is reduced a predetermined amount, the gas will Abe liquefied soas to release the pressure exerted upon the sylphon- 50 and permit the coil spring 27 to force the plate 23 downwardly and reverse the position of the mercury tube 51 so as to break the circuit between the 'electric leads 32 and 33. By reason of the fact that one end of the plate 23 is anchored by means ofthe nut 25, it will be apparent that the action of the sylphon will not constitute a straight vertical movement. One side of the sylphon will tiltwhile the other side, which is closest the anchoring nut 25 will remain relatively stationary. In that manner, the plate 23 will not be raised directly vertically, but will be tilted. v

It will be apparent that theoperating range of the device may be controlled and adjusted through the nut 25, while the temperatures at which the current will be turned oi or on ma be adjusted through the nut 29.

will be obvious that various changes may be made in the arrangement, combination and construction of the various parts of my improved device Without departing from the spirit of my invention, and it is my inten-l tion to cover by my claims such ychanges as may be reasonably included Within the scope thereof.

What I claim is: 4

1. A control device comprising a sylphon, means for expanding the same, a plate overlying the top of the sylphon having a circuit make and break device secured thereon and adapted for actuation by movement of the plate, a standard on one side of the sylphon, means adjustably anchoring the one vend of the plate to the standard, a standard on the other side of the sylphon, the other end of the plate being slidably engaged therewith, and a spring engaged with the latter endof the late for contracting the sylphon under pre etermined conditions.

2. A control device comprising a sylphon, means for expanding the same, a plate overlying the top ,of the sylphon having a circuit make and break devicesecured thereon andadapted for actuation by movement of the plate, a standard on one side of the sylphon, means adjustably anchoring the one end of the plate to the standard, a standard on the other side of the sylphon, the other end of the plate being slidably engaged therewith, a. spring engaged with the latter end of the plate for contracting the sylphon' under predetermined conditions, and means for adjusting the tension of the spring.

3. A control device comprising a sylphon, means for expanding the same,-a plate overlying the top of the sylphon having a circuit make and break device secured thereon and adapted for actuation by movement of the plate, a standard on one side of the sylphon, means adjustably anchoring the one end of the plate to the standard, a standard on the other side of the sylphon, the other end of the plate being slidably engaged therewith, a spring'engaged with the latter end of the plate for contracting the sylphon under predetermined conditions, and means for adjusting the tension of the spring, said means comprlsing a nut threaded onhthe second standard, and adapted to apply pressure on the spring.

4. A control device comprising a sylphon,

means for expanding the' same, aplate overi other side of the sylphon, the other end of the plate being slidably engaged therewith,

4and a cover enveloping the parts and engaged with said standards for securing it in place.

5r A control device comprising a sylphon, means for expanding the same, a pair of standards, one disposed on one side of the sylphon and the other on the opposite side, a

plate resting on the top of the sylphon hav-` ing holes yin each end thereof, one engaged around one standard and the other around the other standard, the surface of the plate around one opening being convex and anut threaded on the Istandard for holding said 'l connected between itsends to said sylphon.

an abutment for one end of said member, means for adjusting the position of said abutment, a spring under compression between the opposite end of said member and a second abutment, means for adjustin the position of said second abutment where y to control the effective pressure of said sprin on the ,corresponding end of 'said member, an

a switch mechanism moved by movement of said member.

GLENN MUFFLY. 

